[1G01-02] Fukushima Daiichi NPP Accident

[1G02] Discussion of Containment Depressurization Scenario of Fukushima Daiichi Unit-2 during March 15th Morning

*Seiichi Dono¹, Kenichiro Nozaki², Takeshi Honda¹, Masato Mizokami¹, Daisuke Yamauchi¹, Shinya Mizokami¹ (1. TEPCO HD, 2. TEPCO SYSTEMS CORPORATION)

Keywords:Fukushima Daiichi, Unit 2, Accident progression, Gas leakage, Condensation, Thermal stratification

The D/W pressure at Fukushima Daiichi Nuclear Power Station Unit-2 dropped from 0.73 MPa [abs] to 0.155MPa [abs] between 7:20 and 11:20 on the March 15th, 2011. We assumed gas leakage from the PCV and steam condensation in the PCV as factors of this depressurization, and examined the feasibility of the accident progression scenario based on the observation facts obtained from the site.